You can easily add a 2nd monitor. Your video card has 2 outputs-one of which you're already using. The only problem is that if you're already using the DVI output, then the only one left is an analog VGA out, which may not look as good.

Your video driver will control the orientation of the monitors, which will allow each monitor to operate independently with it's own refresh rate and resolution. The driver utility will help you determine if a program stays on one screen or can span into the 2nd screen.

Thx deadgnat,

 

One more question, can the monitors be of different size?

The monitors can be a different size-the only difference here is that you won't be able to use the span modes-that's where two monitors act as one large one. Choose dual view, where each monitor can have it's own resolution and refresh rate.